Industrial Solutions
Nitric acidA true all-rounder!
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The power of true effi ciency
The Business Area Industrial Solutions of thyssenkrupp is a world leader for planning, construction and service in the fi eld of industrial plants and systems. Together with our customers we develop solutions at the highest level and deliver effi ciency, reliability and sustainability throughout the entire life cycle. Our global network, with around 19,000 employees at 70 locations, enables us to provi-de turnkey solutions worldwide which set new benchmarks with their high productivity and particularly resource conserving technologies.
We are at home in many different industries. Along with chemical, fertilizer, coking, refi nery, cement and other industrial plants, our portfolio also includes equipment for open-cast mining, ore proces-sing and transshipment, as well as associated services. In the naval sector, we are a leading global system supplier for submarines and surface vessels. As an important system partner to our customers in the automotive, aerospace and battery industries, we optimize the value chain and improve performance.
Contents 04 The history of the Uhde nitric acid
process / Market position
06 The nitric acid process
08 The Uhde medium-pressure process
10 The Uhde high-pressure process
12 The Uhde dual-pressure acid process
14 The Uhde azeotropic nitric acid process
16 The N2O/NO
X abatement process by Uhde – EnviNOx®
19 Typical consumption figures
4
The history of the Uhde nitric acid process / Market position
Mont-Cenis plant
1905 young engineer Friedrich Uhde built the first nitric acid pilot plant
6 April 1921 foundation of Uhde Company
1926 first produced ammonia according to the Mont-Cenis-Uhde-Process
1928 full operation of the plant
1929 first design of a full scale commercial NA process
1932 first commercial scale NA plant in operation (for a customer in Russia)
The founder's first location in Dortmund, Bövinghausen
First commercial nitric acid plant in Russia
The chemical laboratory
5
The oxidation of ammonia over a platinum catalyst to nitrogen oxides, and their ab-sorption in water to form nitric acid was first carried out in 1838 by C.F. Kuhlmann. However, this discovery was not then com-mercialised as ammonia was too expensive compared with the Chile saltpetre used to manufacture nitric acid in those days.
The history of the modern nitric acid pro-cess really begins in 1901 when W. Ostwald established the ammonia oxidation con-ditions necessary for high nitrogen oxide yields. The first plants using the Ostwald process were started up in the first decade of the 20th century.
With more than 55 plants built since 1980 thyssenkrupp Industrial Solutions (formerly known as Uhde) is nowadays the leading licensor for Nitric Acid Technoloy worldwide.
As early as 1905, Dr. Friedrich Uhde, the founder of Uhde GmbH, designed and con-structed, in cooperation with Prof. Wilhelm Ostwald, a pilot plant for the production of nitric acid by burning ammonia with air in the presence of a catalyst.
Since the company’s foundation in 1921, the number of plants for the production of weak and concentrated nitric acid as well as ammonia combustion units for nitrogen oxide production and absorption plants for nitrous waste gases, which have been de-signed, constructed and commissioned by thyssenkrupp Industrial Solutions under a variety of climatic conditions total some 200.
thyssenkrupp Industrial Solutions thus ranks among the world’s leading engineering com- panies engaged in the design and construc-tion of nitric acid plants and ammonia com-bustion units.
The processes have been continually refined in order to meet ever more stringent require-ments, particularly with regard to air pollution control and energy cost constraints.
The plants designed and constructed by thyssenkrupp Industrial Solutions are char-acterised by high reliability, profitability and on-stream time. Shutdown periods are now almost entirely limited to catalyst changes and equipment inspections.
The number of follow-up orders thyssenkrupp Industrial Solutions receives bears witness to the satisfaction of our customers.
6
Although the basic chemistry of the nitric acid process has not changed in the last hundred years, today’s highly efficient, compact and environmentally friendly plants have been developed by a process compa-rable with the advances made in automobile technology in the same period.
Today, nitric acid is produced exclusively from ammonia oxidised by combustion with air in the presence of a noble-metal catalyst.
The catalysts used in the process consist of a pack of platinum-rhodium gauzes, the number depending on the operating pres-sure and burner construction. The gauzes are produced nowadays by knitting thin wires, usually with a diameter of 60 or 76 µm.
A platinum recovery system made from palladium can easily be installed under-neath the platinum catalyst. Combined
catalyst and catchment systems are also available. Nowadays, it is possible to man-ufacture catalyst gauzes with a diameter of more than 5.5 m. More than 1,500 t/day of nitric acid can be produced from a single burner.
Even larger burners can be manufactured; the upper limit is dictated solely by trans-port restrictions and flange machining.
The production of nitric acid takes place in 3 process steps shown by the following main equations:
1. Ammonia combustion 4 NH
3 + 5 O
2 4 NO + 6 H
2O + 905 kJ
2. Oxidation of the nitric oxide 2 NO + O
2 2 NO
2 + 113 kJ
3. Absorption of the nitrogen dioxide in water 3 NO
2 + H
2O
2 HNO
3+ NO + 116 kJ*
In practice, these three process steps can be carried out in different ways, resulting in several different nitric acid processes. Modern nitric acid plants are designed ac-cording to the mono-pressure or the dual-pressure process.
Within the group of mono-pressure pro-cesses, a distinction is made between the medium-pressure process with a 4 - 6 bar abs. operating pressure and the high-pres-sure process which operates at 7 - 12 bar
The dual-pressure process employs a me-dium pressure of approx 4 - 6 bar abs. for ammonia combustion and a high pressure of approx. 10 - 14 bar abs. for nitric acid absorption.
The optimum process is selected taking into account the costs of feedstocks and util-ities, energy and capital investment as well as local conditions.
The nitric acid process
BP Köln, Cologne, Germany
Capacity: 1,500 t/day HNO3 (100%)
Compression
Combustion
Energy recovery
Gas cooling
Absorption
Tail gas treatment
Air
Ammonia
Tail gas
Processwater
Air
NO gas
NO gas
Nitric acid
NO gas+ Acid condensate
Tail gas
Excess energy
NO gas
Tail gas
Block diagram of nitric acid process
abs.
7
In compliance with stringent pollution abate-ment requirements, it is possible to achieve a NO
X tail gas content of below 25 ppm.
Furthermore, emissions of nitrous oxide, an unwanted by-product in the ammonia oxi-dation step, can be reduced to a minimum by the EnviNOx® system by Uhde, which isthe Best Available Technology (BAT) of today.
Nowadays 60 million t/year of nitric acid of various concentrations are produced world-wide. Approximately 85% of this is used as an intermediate in the production of nitrog-
enous mineral fertilizers, primarily ammo-nium nitrate and its derivatives such as cal-cium nitrate, calcium ammonium nitrate and urea ammonium nitrate solution. The remainder goes into the production of porous prilled ammonium nitrate for the mining industry, and as an intermediate for the production of special chemicals such as caprolactam or adipic acid. There is a grow-ing demand for azeotropic nitric acid (ap-proximately 68% concentration), which is used as a nitrating agent in the production of nitro-benzene, dinitrotoluene and other
chemicals. These are further processed to TDI or MDI, and finally used for the pro-duction of polyurethane. thyssenkrupp Industrial Solutions covers many of the technologies mentioned.
Among the great variety of other applica-tions, those most worthy of mention are its use as a chemical in metallurgy, for example as an etching and pickling agent for stainless steel, and its employment in the manufacture of dinitrogen tetroxide for rocket fuels.
Nitric acid
Non-Fertiliser
AN (technical grade)
Capro-lactam
Fertiliser
Chemicals
Adipicacid
Dinitro-toluene
Nitro-benzene
TDI MDI
Poly-amide 6
Poly-amide 6.6
Poly-urethane(flexible PU)
Poly-urethane
(rigid PU)
AN NP
CN CAN UAN ASN
~ 80 % consumption ~ 15 % consumption
Uses of nitric acid
AN : ammonium nitrate
NP : nitrophosphate
CN : calcium nitrate
CAN : calcium ammonium nitrate
UAN : urea ammonium nitrate solution
ASN : ammonium sulphate nitrate
TDI : toluene diisocyanate
MDI : methylene diphenyl diisocyanate
Types of nitric acid plants
Combustion Absorption
Mono medium pressure 4 to 6 bar 4 to 6 bar
Mono high pressure 7 to 12 bar 7 to 12 bar
Dual pressure medium pressure high pressure
4 to 6 bar 10 to 14 bar
Nitric acid plants
Installed capacity since 2000 (World without China)
thyssenkrupp Industrial Solutions
Other licensors
The Uhde medium-pressure process
8
Flowsheet of a medium-pressure
nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser & feedwater preheater
6 Absorption
7 Bleacher
8 Tail gas heater 1 & 2
9 Tail gas reactor
10 Ammonia evaporation & superheating
11 Turbine steam condenser
Nitric acid plant for SKW
in Wittenberg, Germany
Capacity: 350 t/day HNO3 (100%)
(Mono medium-pressure)
The ammonia combustion unit was desi-
gned for a capacity equivalent to 500 t/day
HNO3 (100%). It supplies the existing plant
for the production of highly concentrated
nitric acid with nitrous gases.
9
Ammonia (liquid)
CW
LP steam
CW
Nitric acidproduct
Process water
CW
CW
Tail gas
Secondary air
WB
NO gas
Ammonia (gas)
Tail gasturbine
Steamturbine
Aircompr.
HP steam
Air
Tail gas
1
8
3
4
510 7
9 6
CW CW
WB
STH
HPsteam
WB
11
CW
Condensate
AW
BFWBFW
Primary air
2
Acidcondensate
In this process, the air required for burning the ammonia is supplied by an uncooled air compressor. The compressor set can be designed either as an inline train configura-tion or preferably as a bull gear type with an integrated tail gas turbine.
The operating pressure is governed by the maximum final pressure obtainable in an uncooled compressor, i.e. 4 - 5 bar abs. in the case of radial compressors and 5 - 6 bar abs. with axial flow compressors.
Plant capacities of up to 700 t/day of nitric acid (100%) can be realised using a single ammonia combustion unit and one absorp-tion tower. Due to the process pressure, high-
er capacities of up to about 1,000 t/day are feasible if a second absorption tower is used.The medium pressure process is the pro-cess of choice when maximum recovery of energy is required. The air compressor is usually driven by a tail gas expansion tur-bine and a steam turbine, the steam being generated within the plant. If the credit for exported steam is high then the compressor train can be driven by a high voltage syn-chronous or asynchronous electric motor rather than a steam turbine so that all the steam generated can be exported.
With this plant type, it is possible to pro-duce one type of nitric acid with a max. concentration of 65% or two types of acid
with different concentrations, e.g. 60% nitric acid and 65% nitric acid.
The NOX content has to be reduced to the
required value by selective catalytic reduc-tion using a non-noble-metal catalyst and ammonia as the reducing agent.
The medium-pressure process is charac-terised by a high overall nitrogen yield of about 95.7% or 95.2% in conjunction with the tail gas treatment process, a low platinum consumption and a high steam export rate.
The catalyst gauzes only need to be changed once every 6 months due to the low burner load.
Flowsheet of a medium-pressure
nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser & feedwater preheater
6 Absorption
7 Bleacher
8 Tail gas heater 1 & 2
9 Tail gas reactor
10 Ammonia evaporation & superheating
11 Turbine steam condenser
10
The Uhde high-pressure process
Flowsheet of a high-pressure
nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser & feedwater preheater
6 Absorption
7 Bleacher
8 Tail gas heater 1 & 2
9 Tail gas reactor
10 Ammonia evaporation & superheating
11 Turbine steam condenser
12 Air intercooler
In the high-pressure process, a radial multi- stage compressor with an intercooler sec-tion is used to compress the process air to a final pressure of 7 - 12 bar abs. Prefer-ably, the bull gear type with integrated tail gas turbine is selected but alternatively an inline machine can be used.
Due to the higher pressure, all equipment and piping can be of a smaller size and only one absorption tower is required.
The arrangement of all equipment is very compact so that the building for the machine set and the burner unit can be kept small, but this does not pose a problem for main-tenance work.
This type of plant is always recommended when a quick capital return is desirable.
Plant capacities between 100 t/day (100%) and 1,000 t/day of nitric acid can be realised.
The achieved acid concentrations of up to 67% are slightly higher than with the me-dium-pressure process. Two or more prod-uct streams with different concentrations are likewise possible.
The compressor may be driven by a steam turbine or an electric motor.
The NOX concentration in the tail gas can
be lowered to less than 25 ppm by an addi-tional catalytic tail gas treatment unit. The nitrogen yield attained by the high-pressure process is in the order of 94.5%.
For capacities below 100 t/day, a low capital investment cost may be much more prefer-able to an optimum recovery of energy.
In such cases, thyssenkrupp Industrial Solutions can offer a greatly simplified pro-cess which does not include tail gas and steam turbines. The heating of the tail gas downstream of the absorption section is not necessary. Special design concepts for the process gas cooler unit, condenser and bleacher reduce the cost even further.
thyssenkrupp Industrial Solutions also pro-vides a similar process without the ammonia evaporation and heat recovery units for recovering acid from the waste gas in, for example, adipic acid plants.
11
Tail gasturbine
Steamturbine
Aircompr.
Air
Tail gas
CW
CW
Ammonia (liquid)
CW
LP steam
Acidcondensate
Nitric acidproduct
CW
CW
Process water
Tail gas
LPsteam
WB
NO gas
8
3
4
510 7
9 6
Secondary air
CW
12WB
CW
BFWBFW
CW
AW
Ammonia (gas)
HP steam
11
CW
Condensate
Primary air1
WB
STH
HPsteam
2
Two high-pressure nitric acid plants:
(left) Enaex S.A., Mejillones, Chile
Capacity: 925 t/day HNO3 (100%)
(right) Thai Nitrate Company,
Rayong, Thailand
Capacity: 210 t/day HNO3 (100%)
Flowsheet of a high-pressure
nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser & feedwater preheater
6 Absorption
7 Bleacher
8 Tail gas heater 1 & 2
9 Tail gas reactor
10 Ammonia evaporation & superheating
11 Turbine steam condenser
12 Air intercooler
12
The Uhde dual-pressure acid process
Flowsheet of a high-pressure nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser 1 & feedwater preheater
6 Tail gas heater 2
7 Cooler condenser 2
8 Absorption
9 Tail gas heater 1
10 Tail gas reactor
11 Ammonia evaporation & superheating
12 Ammonia evaporation
13 Bleacher
14 Turbine steam condenser
The dual-pressure process was developed to accommodate ever more stringent envi-ronmental pollution control requirements.
The process air is compressed to a final pressure of 4 - 6 bar abs.
The NO gas from the ammonia combustion unit is cooled in a heat exchanger train, pro- ducing steam and preheating tail gas, and then compressed to 10 - 14 bar abs in the NO
X compressor. The final pressure is se-
lected so as to ensure that the absorption section is optimised for the specified NO
X
content of the tail gas and that the com-pressors, driven by a steam turbine, can be operated using only the steam generated in the process gas cooler unit while ensuring that some excess steam will always be available in order to guarantee steady oper-ating conditions at all times. Alternatively the compressor set can be driven by either a high voltage asynchronous or synchro-nous motor and the steam generated can be exported. The dual-pressure process combines in an economical way the advan-tages of the low pressure in the combustion
section and the high pressure in the absorp- tion section. Plant capacities of up to 1,600 t/day of nitric acid (100%) can be achieved in a single-train configuration. The machine set can be designed either as an inline-shaft set or optionally as a bull gear type unit with integrated air/NO
X compression and tail gas
expander stages. The inline machine con-cept is favourable in the case of higher plant capacities from 500 t/day up to 2,200 t/day or if an increased energy export is required.
The NOX is further reduced to less than 25
ppm by selective catalytic reduction using a non-noble-metal catalyst and ammonia as the reducing agent.
Due to the low burner load, the catalyst gauzes can remain in the burner for an oper- ating period of 6 to 8 months or longer be-fore being partially or completely replaced.
Acid concentrations of more than 68% can be achieved. Two or more product streams with different concentrations are also possi-ble. In addition, external streams of weak nitric acid (various concentrations) can be processed if required.
13
Tail gasturbine
Aircompr.
NOx
compr.
Steamturbine
CW
Ammonia (liquid)
LP steam
LP steam
CW
WB
Nitric acidproduct
CW
CW
Process water
CW
CW
CW
Air
HP steam Condensate
Tail gas
Secondary air
NO gas
Tail gas
BFW
Tail gas
Ammonia (gas)
1 6
7 9
3
4
511 1312
10 8
2
14
CW
BFW
CW
Primary air
Acidcondensate
WB
STH
HPsteam
AW
Two dual-pressure nitric acid plants:
(left) Abu Qir Fertilizers and Chemical Ind. Co.,
Abu Qir, Egypt
Capacity: 1,850 t/day HNO3 (100%)
NOX in tail gas: less than 50 ppm as a result
of a catalytic tail gas treatment process
(right) Borealis AG, Linz, Austria
Capacity: 1,000 t/day HNO3 (100%)
NOX in tail gas: less than 10 ppm
as a result of the N2O/NO
X abatement
process by Uhde – EnviNOx®
Flowsheet of a high-pressure nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser 1 & feedwater preheater
6 Tail gas heater 2
7 Cooler condenser 2
8 Absorption
9 Tail gas heater 1
10 Tail gas reactor
11 Ammonia evaporation & superheating
12 Ammonia evaporation
13 Bleacher
14 Turbine steam condenser
14
The Uhde azeotropic nitric acid process
Flowsheet of an azeotropic nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser 1 & feedwater preheater
6 Tail gas heater 2
7 Cooler condenser 2
8 Absorption
9 Tail gas heater 1
10 Tail gas reactor
11 Ammonia evaporation & superheating
12 Ammonia evaporation
13 Bleacher
14 Turbine steam condenser
15 Air condenser (optional)
Azeotropic nitric acid with an elevated con-centration of 68% by weight can replace concentrated nitric acid in some applica-tions such as nitrations. Due to increased market demand, we have developed an en-hanced process for the reliable production of azeotropic nitric acid without any further weak nitric acid co-production. The basic process design is mainly an extended dual-pressure process.
Important process features for the produc-tion of azeotropic acid are, in addition to sufficient absorption pressure and cooling, the overall water balance of the plant. Fur-thermore, the ratio of dinitrogen tetroxide to nitric oxide in the process gas at the absorp- tion tower inlet has to be adjusted to a level that is in equilibrium with the acid concen-tration required.
To satisfy the overall water balance, it is mandatory at some locations to eliminate the water carried with the incoming air taken in by the air compressor. The necessary measures depend on climatic conditions, in particular air humidity and temperature. In the case of extreme conditions the installa-tion of an additional air cooler/condenser operating partly with chilled water is recom-mended. Normally in the Uhde dual-pres-sure process, there is an extra chilled water circuit linked to the ammonia evaporation. This uses to a large extent the ammonia evaporation heat, especially in the absorp-tion section, in order to establish the re-
quired acid strength and the NOX level at the
absorption outlet. It is also possible to pro-vide an external chilled water set. However, this solution is expensive and energy con-suming and would only be considered by thyssenkrupp Industrial Solutions if all other measures prove insufficient.
The design of the absorption column is of particular importance especially for pro-ducing azeotropic acid. At thyssenkrupp Industrial Solutions a sophisticated com-puter program is used to predict the exact limits of acid concentration, heat loads, NO
X
in tail gas, etc.
Another important feature of the azeotropic nitric acid process by Uhde is the drying section for the secondary air.
Taking the above into consideration, thyssenkrupp Industrial Solutions is able to offer individual customers tailor-made solu-tions for azeotropic nitric acid plants.
The equipment shown as an example is fully integrated in thyssenkrupp Industrial Solutions´ compact bull gear concept, which is applicable for capacities up to 1,100 t/day. Above this capacity an inline machine set is employed as shown on page 13. The first pressure level delivered by the air compres-sor is advantageous for the ammonia com-bustion section, while the final pressure de- livered by the NO
X compressor promotes ab-
sorption and the formation of azeotropic acid.
15
NOx
compr.
Tail gasturbine
Steamturbine
Aircompr.
HP steamAir
CW
Ammonia (liquid)
LP steam
CW
AW
LP steam
Acidcondensate
CW
WB
BFW
3
511 12
Nitric acid product
CW
CW
Process water
CW
CW
Tail gas
Tail gas
1 6
13
Tail gas
15
Ammonia (gas)
CW
(optional)
AW
NO gas2 7 9
4108
14
CW
BFW
Secondary air
Primary air
CW
Condensate
WB
STH
HPsteam
Two azeotropic nitric acid plants:
(left) BP Köln, Cologne, Germany
Capacity: 1,500 t/day HNO3 (100%)
(right) Namhae Chemical Corporation
operated by HU-CHEMS, Yosu, Korea
Capacity: 1,150 t/day HNO3 (100%)
Flowsheet of an azeotropic nitric acid plant
1 Reactor
2 Process gas cooler
3 Tail gas heater 3
4 Economizer
5 Cooler condenser 1 & feedwater preheater
6 Tail gas heater 2
7 Cooler condenser 2
8 Absorption
9 Tail gas heater 1
10 Tail gas reactor
11 Ammonia evaporation & superheating
12 Ammonia evaporation
13 Bleacher
14 Turbine steam condenser
15 Air condenser (optional)
16
The N2O/NO
X abatement process by Uhde – EnviNOx®
EnviNOx® reactor at
Borealis AG, Linz, Austria
Capacity: 1,000 t/day HNO3 (100%)
Neglected for many years, nitrous oxide (N
20) – also known as “laughing gas” - is
formed in the ammonia burner as an un-wanted by-product. Depending on the performance of this burner around 1% to 2% of the ammonia feed is lost in this way, with a similar amount being lost due to the formation of nitrogen. The nitrous oxide passes through the rest of the nitric acid plant unchanged and is discharged to at-mosphere with the tail gas. Emissions are now coming under scrutiny by regulators since nitrous oxide is a potent greenhouse gas some 300 times stronger than carbon dioxide and is implicated in the destruction of the ozone layer.
thyssenkrupp Industrial Solutions, having at an early stage recognised this trend, have developed a catalyst and a process for the lowering of nitrous oxide emissions from nitric acid plants. An added bonus is that emissions of nitrogen monoxide and dioxide (NO
X) are also reduced.
The EnviNOx® nitrogen oxide abatement process by Uhde features a tail gas reactor installed directly upstream of the tail gas turbine. thyssenkrupp Industrial Solutions has developed specific process variants to cater for the range of temperatures found in different nitric acid plants. The nitrous oxide decomposition (variant 1) is particularly suited to tail gas temperatures above 420°C. In this variant nitrous oxide is decomposed to oxygen and nitrogen in a first catalyst bed.
N20
N
2 + ½ O
2 + 82 kJ
The tail gas is then mixed with ammonia before entering the second bed in which NO
X is catalytically reduced to water vapour
and nitrogen:
4NO + 4NH3+O
2 4N
2+ 6H
2O + 1628 kJ
3NO2 + 4NH
3 7/2N
2+ 6H
2O + 1367 kJ
Further removal of nitrous oxide also takes place in this bed.
For lower temperatures thyssenkrupp Industrial Solutions’ solution is based on the catalytic reduction of nitrous oxide with hydrocarbons, such as natural gas, com-bined with the reduction of NO
X by ammonia
(variant 2). In most situations the removal of both N
2O and NO
X can take place in par-
allel in a single catalyst bed. The quantity of the greenhouse gas carbon dioxide, that is produced due to the use of hydrocarbons is insignificant in comparison to the amount of greenhouse gas emission reduction that the EnviNOx® process achieves by the removal of nitrous oxide.
In both EnviNOx® process variants the tail gas leaving the reactor has reduced con-centration of N
2O of 30 ppm. The low outlet
NOX concentration is significantly smaller
than that commonly attained in conventional DeNO
X units, and results in an invisible stack
plume. The NOX reduction component is
also available without the N2O removal com-
ponent and is applicable to temperatures between about 200°C and 500°C.
EnviNOx® technology by Uhde is suited equally well to retrofits or to new plants. As it is an end-of-pipe process there is no contact with the product nitric acid or inter-mediate NO gas, thus eliminating any pos-sibility of product loss or contamination.
For more details, please refer to our brochure: An environmental star: EnviNOx®
Ammonia (gas)
Tail gasturbine
Hydrocarbon
Nitric acid
CW
CW
Process water
Tail gas
Tail gas
1
NO gas
3
2
17
Tail gasturbine
Nitric acid
CW
CW
Process water
Tail gas
Tail gas
1
NO gas
Ammonia (gas)3
2
1 Absorption
2 Tail gas heating
3 EnviNOx® combining DeN
2O and DeNO
x
functions
1 Absorption
2 Tail gas heating
3 EnviNOx® combining DeN
2O and DeNO
x
functions
Flowsheet of tail gas section of a nitric acid plant with EnviNOx® reactor (variant 1)
Flowsheet of tail gas section of a nitric acid plant with EnviNOx® reactor (variant 2)
(for lower temperature applications)
18
The dual-pressure nitric acid plant in
Donaldsonville, Louisiana, USA.
Capacity: 870 t/day HNO3 (100%)
19
Typical consumption figures
Note: Comparison of typical consumption figures for steam turbine-driven and inline compressor set nitric acid plants,
per tonne of nitric acid (100%)
Plant type Medium-pressureprocess
High-pressureprocess
Dual-pressureprocess
Operating pressure pabs
Ammonia
Electric power
Platinum, primary losses
with recovery
Cooling water(∆t =10 K)including waterfor steam turbine condenser
Process water
LP heating steam,8 bar, saturated
HP excess steam,
5.8 bar
284.0 kg
9.0 kWh
0.15 g
0.04 g
100 t
0.3 t
0.05 t
0.76 t
10.0 bar
286.0 kg
13.0 kWh
0.26 g
0.08 g
130 t
0.3 t
0.20 t
0.55 t
4.6/12.0 bar
282.0 kg
8.5 kWh
0.13 g
0.03 g
105 t
0.3 t
0.05 t
0.65 t40 bar, 450 °C
PT 0
14/0
/e/5
00/2
0150
6/PM
/Prin
ted
in G
erm
any
PT 0
14/1
/e/3
00/2
0170
1/S
Z/Pr
inte
d in
Ger
man
y
Industrial SolutionsFertilizer and Syngas Technologies
thyssenkrupp Industrial Solutions AG Friedrich-Uhde-Straße 15 44141 Dortmund GermanyP: +49 231 547 0 F: +49 231 547 10 www.thyssenkrupp-industrial-solutions.com